Libya Leader Finally Picked but Is Quickly Challenged

TRIPOLI, Libya — After a long search, Libya’s transitional Parliament appeared to have finally selected a new prime minister on Sunday, choosing Ahmed Maitiq, a businessman, during a chaotic legislative session.

But almost as soon as Mr. Maitiq was sworn in, lawmakers who said the vote had been conducted improperly challenged his appointment. As a result, it remained unclear whether the caretaker prime minister whom Mr. Maitiq was supposed to replace was willing to leave his post.

The confusion was another blow to a transitional government that has struggled to find coherence since the fall of the dictator Col. Muammar el-Qaddafi in 2011. Parliament’s work has been undermined by internal squabbling and threatened by the country’s fractious militias, composed of men who fought Colonel Qaddafi during the uprising and were never disarmed.

Sunday’s vote was the latest of several attempts to choose a prime minister. Another vote was abandoned last week when armed men stormed Parliament and lawmakers fled.

The search for a new prime minister has been underway in earnest since March, when Parliament voted to remove Ali Zeidan from the position. He had survived several other attempts to remove him, mostly because lawmakers could not find a replacement. He was succeeded by the current caretaker prime minister, Abdullah al-Thinni, the former defense minister, who was supposed to occupy the post for only two weeks during the search for a permanent replacement.

If he lasts in the position, Mr. Maitiq will be the fifth prime minister since Colonel Qaddafi’s fall. He would step into a seemingly thankless and often dangerous post: Mr. Zeidan was kidnapped at one point, and Mr. Thinni’s family was attacked in their home.

Like many of the political figures who have assumed senior roles during the transition, Mr. Maitiq was previously unknown to most Libyans. He is from a prominent family in Misurata, the western coastal town that has emerged as a powerful city-state in the last three years. Mr. Maitiq studied international business in London, he said during an address to Parliament.

Officials said he had two weeks to form a cabinet, but an effort was underway late Sunday to challenge the election of Mr. Maitiq. A group of lawmakers argued that his selection was invalid because the vote was conducted without a quorum, when Parliament had adjourned after an inconclusive first round of voting.

An official close to Mr. Thinni who requested anonymity because he was not authorized to speak to the news media raised the likelihood of yet another parliamentary feud. “As long as the procedure was unconstitutional,” he said, “there won’t be any handing over.”

Suliman Ali Zway reported from Tripoli, and Kareem Fahim from Cairo.

A version of this article appears in print on , on Page A8 of the New York edition with the headline: Libya Leader Finally Picked but Is Quickly Challenged. Order Reprints | Today’s Paper | Subscribe